Shock test assembly

ABSTRACT

An assembly for shock testing a specimen, the assembly including first and second opposing brackets and opposing lower and upper caps. The opposing brackets include lower and upper angled surfaces. The lower cap includes lower angled surfaces configured to engage the lower angled surfaces of the left and right brackets. The upper cap includes upper angled surfaces configured to engage the upper angled surfaces of the left and right brackets. The first and second brackets are configured to be drawn toward each other via fasteners, thereby wedging the lower and upper caps toward each other against the specimen.

GOVERNMENT INTERESTS

This invention was made with Government support under Contract No.:DE-NA0002839 awarded by the United States Department of Energy/NationalNuclear Security Administration. The Government has certain rights inthe invention.

BACKGROUND

Shock test assemblies are often used for securing specimens to a shocktable via a combination of plates, blocks, and/or inserts. Forcesrequired to secure a specimen during shock tests are typically absorbedby clamping bolts, which results in high edge loading on the specimen.At extremely high levels of shock, clamping bolts may be stressed tofailure. Such shock test assemblies also work only in one orientation,thus requiring six shock test assemblies to fully test a singlespecimen.

SUMMARY

Embodiments of the invention solve the above-mentioned problems andother problems and provide a distinct advancement in the art of shocktest assemblies. More particularly, the invention provides a shock testassembly that more effectively secures a specimen.

An embodiment of the shock test assembly broadly comprises opposingfirst and second brackets, opposing lower and upper caps, a number offasteners, and a number of accelerometers. The shock test assembly maybe made of aluminum, titanium, or any other suitable material.

The first and second brackets are substantially similar so only thefirst bracket will be described in detail. The first bracket includes abase, a riser, a through-space, a lower angled surface, and an upperangled surface. The first bracket may have an L-shape, an invertedT-shape, or any other suitable shape.

The base includes a number of vertical fastener holes and a number ofaccelerometer mounting points. The base may be a flange, a plate, afoot, or any other suitable support structure.

The vertical fastener holes receive fasteners therethrough for mountingthe first bracket to a shock table. The vertical fastener holes areslotted for allowing the first and second brackets to be drawn together.

The accelerometer mounting points may be bolt holes, screw holes,flanges, or the like. In one embodiment, the accelerometer mountingpoints are positioned on a top surface of the base for mounting some ofthe accelerometers onto the base.

The riser is an inverted U-shaped structure extending vertically fromthe top surface of the base. The riser frames the lower cap and uppercap via the through-space.

The through-space extends horizontally through the riser foraccommodating at least a portion of the lower cap and at least a portionof the upper cap. The through-space may be bounded on its lower end bythe lower angled surface and on its upper end by the upper angledsurface.

The lower angled surface slopes downward from the top surface of thebase to a front surface of the base at a lower end of the through-spacebetween the left and right vertical legs. The lower angled surface maybe inclined between one degree and thirty degrees. The inclination ofthe lower angled surface may match an inclination of an angled surfaceof the lower cap.

The upper angled surface slopes upward on a bottom side of thehorizontally extending cross-member between the left and right verticallegs. The upper angled surface may be inclined between one and thirtydegrees. The inclination of the upper angled surface may match aninclination of an angled surface of the upper cap. In one embodiment,the inclinations of the upper angled surface and lower angled surfaceare equal but opposite.

The lower cap includes an upper surface, a lip, and opposing first andsecond lower angled surfaces. The lower cap may have an inverted doublewedge shape.

The upper surface is a horizontally-extending upward facing surface forsupporting the specimen. To that end, the upper surface may besubstantially flat or may have recesses, grooves, ridges, alignmentnubs, or other geometry for accommodating various specimen shapes orfeatures. The upper surface may be rectangular or any other suitableshape.

The lip is a raised ledge encircling a perimeter of the upper surface.The lip retains the specimen on the upper surface. The lip may have ashape matching the shape of the upper surface.

The first lower angled surface slopes upward on a bottom side of thelower cap and may be inclined between one and thirty degrees. Aninclination of the first lower angled surface may match an inclinationof the lower angled surface of the first bracket.

The second lower angled surface slopes upward on the bottom side of thelower cap opposite the first lower angled surface and may be inclinedbetween one and 30 degrees. An inclination of the second lower angledsurface may match an inclination of the lower angled surface of thesecond bracket.

The upper cap includes a lower surface, a lip, and first and secondupper angled surfaces. The upper cap may have a double wedge shape. Inone embodiment, the upper cap is substantially similar to the lower capexcept inverted.

The lower surface is a horizontally-extending downward facing surfaceconfigured to abut a top of the specimen. To that end, the lower surfacemay be substantially flat or may have recesses, grooves, ridges,alignment nubs, or other geometry for accommodating various specimenshapes or features. The lower surface may be rectangular or any othersuitable shape.

The lip is a lowered ledge encircling a perimeter of the lower surface.The lip retains the specimen in abutment with the lower surface. The lipmay have a shape matching the shape of the lower surface.

The first upper angled surface slopes downward on a top side of theupper cap and may be inclined between one and thirty degrees. Aninclination of the first upper angled surface may match an inclinationof the upper angled surface of the first bracket.

The second upper angled surface slopes downward on the top side of theupper cap opposite the first upper angled surface and may be inclinedbetween one and thirty degrees. An inclination of the second upperangled surface may match an inclination of the upper angled surface ofthe second bracket.

The fasteners may be bolts, rods, clamps, or the like for securing thefirst and second brackets together. In one embodiment, the fastenersinclude four bolts inserted through horizontal fastener holes of thefirst bracket and received in horizontal fastener holes of the secondbracket.

The accelerometers detect acceleration of the shock test assembly andhence the specimen. The accelerometers may be piezoelectricaccelerometers, strain gauges, capacitive accelerometers, or the like.The accelerometers may be mounted on or attached to the first and secondbrackets, the lower cap, and/or the upper cap.

In use, the shock test assembly can shock test an approximately 1 poundspecimen to over 20,000 g acceleration in two orientations. That is, thelower cap, upper cap, and specimen (or the specimen by itself in someembodiments) can be turned upside down such that the specimen can beshock tested in an upright orientation and in an upside-downorientation. As such, three shock test assemblies can fully test aspecimen in six orientations.

To test the specimen in a desired orientation, the specimen may bepositioned on the upper surface of the lower cap. A lower surface of thespecimen may be flush against the upper surface with the lip encirclingthe specimen.

The upper cap may then be positioned on the specimen opposite the lowercap. An upper surface of the specimen may be flush against the lowersurface with the lip encircling the specimen.

The lower cap, specimen, and upper cap may then be at least partiallyinserted into the through-spaces of the left and right brackets so thatthe first and second brackets bookend the lower cap, specimen, and uppercap. At this point, the first lower angled surface of the lower cap mayabut the lower angled surface of the first bracket. The second lowerangled surface of the lower cap may abut the lower angled surface of thesecond bracket. The first upper angled surface of the upper cap may abutthe upper angled surface of the first bracket. The second upper angledsurface of the upper cap may abut the upper angled surface of the secondbracket.

Bracket fasteners may then be inserted through the horizontal fastenerholes of the first bracket and into the horizontal fastener holes of thesecond bracket. Mounting fasteners may also be inserted into thevertical fastener holes but not tightened.

The bracket fasteners may then be tightened so as to draw the firstbracket and second bracket toward each other. The first and secondbrackets in turn impart a compressive force to the lower cap, specimen,and upper cap via the angled surfaces. This evenly distributes thecompressive force between the lower cap and upper cap so that thespecimen is evenly compressed. The oblong vertical fastener holes allowthe first bracket and second bracket to be drawn toward each otherwithout imparting a shearing or bending force on the mounting fasteners.The mounting fasteners may then be tightened so as to secure the shocktest assembly to the shock table.

The accelerometers may then be connected, communicatively coupled,and/or linked to a data collection, processing, and analyzing computingsystem. For example, wires may be connected between the accelerometersand the computing system. Alternatively, the accelerometers maycommunicate wirelessly with the computing system.

A shock or shocks may then be applied to the shock test assembly andhence to the specimen. The accelerometers in turn transmit accelerationdata to the computing system. Shocks may be applied until the desiredamount of data is obtained.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Other aspectsand advantages of the present invention will be apparent from thefollowing detailed description of the embodiments and the accompanyingdrawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the present invention are described in detail below withreference to the attached drawing figures, wherein:

FIG. 1. is a perspective view of a shock test assembly constructed inaccordance with an embodiment of the invention is illustrated;

FIG. 2 is a plan view of the shock test assembly of FIG. 1;

FIG. 3 is a front elevation cross section view of the shock testassembly of FIG. 1;

FIG. 4 is an exploded view of the shock test assembly of FIG. 1; and

FIG. 5 is a flow diagram including some steps of a method of shocktesting a specimen via the shock test assembly of FIG. 1.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following detailed description of the invention references theaccompanying drawings that illustrate specific embodiments in which theinvention can be practiced. The embodiments are intended to describeaspects of the invention in sufficient detail to enable those skilled inthe art to practice the invention. Other embodiments can be utilized andchanges can be made without departing from the scope of the presentinvention. The following detailed description is, therefore, not to betaken in a limiting sense. The scope of the present invention is definedonly by the appended claims, along with the full scope of equivalents towhich such claims are entitled.

In this description, references to “one embodiment”, “an embodiment”, or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment”, “an embodiment”, or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments, but is not necessarily included.Thus, the current technology can include a variety of combinationsand/or integrations of the embodiments described herein.

Turning to FIGS. 1-4, an assembly 10 for shock testing a specimen 100 isillustrated. The shock test assembly 10 broadly comprises a firstbracket 12, a second bracket 14, a lower cap 16, an upper cap 18, aplurality of fasteners 20, and a plurality of accelerometers 22. Theshock test assembly 10 may be made of aluminum, titanium, or the likeand may be machined, stamped, molded, or additively manufactured.

The first bracket 12 includes a base 24, a riser 26, a through-space 28,a lower angled surface 30, and an upper angled surface 32. The firstbracket 12 may be L-shaped (as best seen in FIG. 3), inverted T-shaped,or any other suitable shape.

The base 24 may be a flange, a plate, a foot, or any other suitablesupport structure and includes a top surface 34, a plurality of verticalfastener holes 36, and a plurality of accelerometer mounting points 38.The base 24 supports the riser 26 on a shock table or the like.

The vertical fastener holes 36 may be oblong slots (the purpose of whichwill be described below) configured to receive mounting fastenerstherethrough. In one embodiment, the first bracket 12 includes 5vertical fastener holes 36 spaced from each other and laterally spacedfrom the riser 26 near an outer perimeter of the base 24.

The accelerometer mounting points 38 may be bolt holes, screw holes,flanges, or the like. In one embodiment, the accelerometer mountingpoints 38 are positioned on the top surface 34 for mounting some of theaccelerometers 22 onto the base 24.

The riser 26 may include left and right vertical legs 40, 42, ahorizontally extending cross-member 44, and a plurality of horizontalfastener holes 46. In one embodiment, the riser 26 is an invertedU-shaped structure extending vertically from the top surface 34 of thebase 24. The riser 26 frames the lower cap 16 and upper cap 18 via thethrough-space 28.

The horizontal fastener holes 46 may be circular holes, oblong slots, orthe like for receiving fasteners 20 therethrough. In one embodiment, thehorizontal fastener holes 46 include left and right lower horizontalfastener holes and left and right upper horizontal fastener holespassing through the left and right vertical legs 40, 42. The horizontalfastener holes 46 are configured to align with horizontal fastener holesof the second bracket 14.

The through-space 28 extends horizontally through the riser 26 foraccommodating at least a portion of the lower cap 16 and at least aportion of the upper cap 18. The through-space 28 may be bounded on itslower end by the lower angled surface 30 and on its upper end by theupper angled surface 32. The through-space may be substantiallyrectangular although other shapes may be used depending on shapes of thelower cap 16 and upper cap 18.

The lower angled surface 30 slopes downward from the top surface 34 ofthe base 24 to a front surface of the base 24 at a lower end of thethrough-space 28 between the left and right vertical legs 40, 42. Thelower angled surface 30 may be inclined between one degree and thirtydegrees. The inclination of the lower angled surface 30 may match aninclination of an angled surface of the lower cap 16.

The upper angled surface 32 slopes upward on a bottom side of thehorizontally extending cross-member 44 between the left and rightvertical legs 40, 42. The upper angled surface 32 may be inclinedbetween one and thirty degrees. The inclination of the upper angledsurface 32 may match an inclination of an angled surface of the uppercap 18. In one embodiment, the inclinations of the upper angled surface32 and lower angled surface 30 are equal but opposite.

The second bracket 14 includes a base 48, a riser 50, a through-space52, a lower angled surface 54, an upper angled surface 56. The secondbracket 14 may be L-shaped (as best seen in FIG. 3), inverted T-shaped,or any other suitable shape.

The base 48 may be a flange, a plate, a foot, or any other suitablesupport structure and includes a top surface 58, a plurality of verticalfastener holes 60, and a plurality of accelerometer mounting points 62.The base 48 supports the riser 50 on a shock table or the like.

The vertical fastener holes 60 may be oblong slots (the purpose of whichwill be described below) configured to receive mounting fastenerstherethrough. In one embodiment, the second bracket 14 includes fivevertical fastener holes 60 spaced from each other and laterally spacedfrom the riser 50 near an outer perimeter of the base 48.

The accelerometer mounting points 62 may include bolt holes, screwholes, flanges, or the like. In one embodiment, the accelerometermounting points 62 are positioned on the top surface 58 for mountingsome of the accelerometers 22 onto the base 48.

The riser 50 may include left and right vertical legs 64, 66, ahorizontally extending cross-member 68, and a plurality of horizontalfastener holes 70. In one embodiment, the riser 50 is an invertedU-shaped structure extending vertically from the top surface 58 of thebase 48. The riser 50 frames the lower cap 16 and upper cap 18 via thethrough-space 52.

The horizontal fastener holes 70 may be circular holes, oblong slots, orthe like for receiving ends of the fasteners 20. To that end, thehorizontal fastener holes 70 may be threaded for securing bolts. In oneembodiment, the horizontal fastener holes 70 include left and rightlower horizontal fastener holes and left and right upper horizontalfastener holes extending into the left and right vertical legs 64, 66.The fastener holes 70 are configured to align with the horizontalfastener holes 70 of the first bracket 12.

The through-space 52 extends horizontally through the riser 50 foraccommodating at least a portion of the lower cap 16 and at least aportion of the upper cap 18. The through-space 52 may be bounded on itslower end by the lower angled surface 54 and on its upper end by theupper angled surface 56. The through-space may be substantiallyrectangular although other shapes may be used depending on shapes of thelower cap 16 and upper cap 18.

The lower angled surface 54 slopes downward from the top surface 58 ofthe base 48 to a front surface of the base 48 at a lower end of thethrough-space 52 between the left and right vertical legs 64, 66. Thelower angled surface 54 may be inclined between one degree and thirtydegrees. The inclination of the lower angled surface 54 may match aninclination of an angled surface of the lower cap 16.

The upper angled surface 56 slopes upward on a bottom side of thehorizontally extending cross-member 68 between the left and rightvertical legs 64, 66. The upper angled surface 56 may be inclinedbetween one and thirty degrees. The inclination of the upper angledsurface 56 may match an inclination of an angled surface of the uppercap 18. In one embodiment, the inclinations of the upper angled surface56 and lower angled surface 54 are equal but opposite.

The lower cap 16 includes an upper surface 72, a lip 74, opposing firstand second lower angled surfaces 76, 78, and an accelerometer mountingpoint 80. The lower cap 16 may have an inverted double wedge shape, asbest seen in FIG. 3.

The upper surface 72 is a horizontally-extending upward facing surfacefor supporting the specimen 100. To that end, the upper surface 72 maybe substantially flat or may have recesses, grooves, ridges, alignmentnubs, or other geometry for accommodating various specimen shapes orfeatures. The upper surface 72 may be rectangular or any other suitableshape.

The lip 74 is a raised ledge encircling a perimeter of the upper surface72. The lip 74 retains the specimen 100 on the upper surface 72. The lip74 may have a shape matching the shape of the upper surface 72.

The first lower angled surface 76 slopes upward on a bottom side of thelower cap 16 and may be inclined between one and 30 degrees. Aninclination of the first lower angled surface 76 may match aninclination of the lower angled surface 30 of the first bracket 12.

The second lower angled surface 78 slopes upward on the bottom side ofthe lower cap 16 opposite the first lower angled surface 76 and may beinclined between one and 30 degrees. An inclination of the second lowerangled surface 78 may match an inclination of the lower angled surface54 of the second bracket 14.

The accelerometer mounting point 80 may include bolt holes, screw holes,flanges, or the like. In one embodiment, the accelerometer mountingpoint 80 is positioned on a bottom side of the lower cap 16 between thefirst and second lower angled surfaces 76, 78 for mounting one of theaccelerometers 22 onto the lower cap 16.

The upper cap 18 includes a lower surface 82, a lip 84, first and secondupper angled surfaces 86, 88, and an accelerometer mounting point 90.The upper cap 18 may have a double wedge shape, as best seen in FIG. 3.In one embodiment, the upper cap 18 is substantially similar to thelower cap 16 except inverted.

The lower surface 82 is a horizontally-extending downward facing surfaceconfigured to abut a top of the specimen 100. To that end, the lowersurface 82 may be substantially flat or may have recesses, grooves,ridges, alignment nubs, or other geometry for accommodating variousspecimen shapes or features. The lower surface 82 may be rectangular orany other suitable shape.

The lip 84 is a lowered ledge encircling a perimeter of the lowersurface 82. The lip 84 retains the specimen 100 in abutment with thelower surface 82. The lip 84 may have a shape matching the shape of thelower surface 82.

The first upper angled surface 86 slopes downward on a top side of theupper cap 18 and may be inclined between one and 30 degrees. Aninclination of the first upper angled surface 86 may match aninclination of the upper angled surface 32 of the first bracket 12.

The second upper angled surface 88 slopes downward on the top side ofthe upper cap 18 opposite the first upper angled surface 86 and may beinclined between one and 30 degrees. An inclination of the second upperangled surface 88 may match an inclination of the upper angled surface56 of the second bracket 14.

The accelerometer mounting point 90 may include bolt holes, screw holes,flanges, or the like. In one embodiment, the accelerometer mountingpoint 90 is positioned on a top side of the upper cap 18 between thefirst and second upper angled surfaces 86, 88 for mounting one of theaccelerometers 22 onto the upper cap 18.

The fasteners 20 may be bolts, rods, clamps, or the like for securingthe first and second brackets 12, 14 together. In one embodiment, thefasteners 20 include four bolts inserted through the horizontal fastenerholes 46 of the first bracket 12 and received in the horizontal fastenerholes 70 of the second bracket 14.

The accelerometers 22 detect acceleration of the shock test assembly 10and hence the specimen 100. The accelerometers 22 may be piezoelectricaccelerometers, strain gauges, capacitive accelerometers, or the like.In one embodiment, the accelerometers are 3991A1020KG modelaccelerometers manufactured by PCB Piezotronics. The accelerometers maybe mounted on or attached to the first and second brackets 12, 14, thelower cap 16, and the upper cap 18 via the accelerometer mounting points38, 62, 80, 90.

Turning to FIG. 5 and with reference to FIGS. 1-4, use of the shock testassembly 10 will now be described in more detail. First, the specimen100 may be positioned on the upper surface 72 of the lower cap 16, asshown in block 200. A lower surface of the specimen 100 may be flushagainst the upper surface 72 with the lip 74 encircling the specimen100.

The upper cap 18 may then be positioned on the specimen 100 opposite thelower cap 16, as shown in block 202. An upper surface of the specimen100 may be flush against the lower surface 82 with the lip 84 encirclingthe specimen 100.

The lower cap 16, specimen 100, and upper cap 18 may then be at leastpartially inserted into the through-spaces 28, 52 of the left and rightbrackets 12, 14 so that the first and second brackets 12,14 bookend thelower cap 16, specimen 100, and upper cap 18, as shown in block 204. Atthis point, the first lower angled surface 76 of the lower cap 16 mayabut the lower angled surface 30 of the first bracket 12. The secondlower angled surface 78 of the lower cap 16 may abut the lower angledsurface 54 of the second bracket 14. The first upper angled surface 86of the upper cap 18 may abut the upper angled surface 32 of the firstbracket 12. The second upper angled surface 88 of the upper cap 18 mayabut the upper angled surface 56 of the second bracket 14.

The fasteners 20 may then be inserted through the horizontal fastenerholes 46 of the first bracket 12 and into the horizontal fastener holes70 of the second bracket 14, as shown in block 206. Mounting fastenersmay also be inserted into the vertical fastener holes 36, 60 but nottightened, the purpose of which will be described below.

The fasteners 20 may then be tightened so as to draw the first bracket12 and second bracket 14 toward each other, as shown in block 208. Thefirst and second brackets 12, 14 in turn impart a compressive force tothe lower cap 16, specimen 100, and upper cap 18 via the angledsurfaces. This evenly distributes the compressive force between thelower cap 16 and upper cap 18 so that the specimen 100 is evenlycompressed. The oblong vertical fastener holes 36 allow the firstbracket 12 and second bracket 14 to be drawn toward each other withoutimparting a shearing or bending force on the mounting fasteners. Themounting fasteners may then be tightened so as to secure the shock testassembly 10 to a shock table or other external structure, as shown inblock 210.

The accelerometers 22 may then be connected, communicatively coupled,and/or linked to a data collection, processing, and analyzing computingsystem, as shown in block 212. For example, wires may be connectedbetween the accelerometers 22 and the computing system. Alternatively,the accelerometers may communicate wirelessly with the computing system.

A shock or shocks may then be applied to the shock test assembly 10 andhence to the specimen 100, as shown in block 214. The accelerometers 22in turn transmit acceleration data to the computing system. Step 214 maybe repeated until the desired amount of data is obtained.

The above-described shock test assembly 10 and method provide severaladvantages. For example, the shock test assembly 10 can be used to testan approximately 1 pound specimen to over 20,000 g acceleration in twoorientations. For example, the lower cap 16, upper cap 18, and specimen100 (or the specimen 100 by itself in some embodiments) can be turnedupside down such that the specimen 100 can be shock tested in an uprightorientation and in an upside-down orientation. As such, three shock testassemblies can fully test a specimen in six orientations. The shock testassembly 10 can withstand multiple tests and test iterations and doesnot damage the specimen 100 before, during, or after a shock event.

The wedge shapes of the lower cap 16 and upper cap 18 and thenon-parallel angle between the horizontal fasteners 20 and the directionof the compressive force provide a mechanical advantage for compressionof the specimen 100. Specifically, the mechanical advantage of the wedgeshapes is the ratio of the length of a wedge divided by the width of thewedge. Advantageously, the mechanical advantage can be chosen (orchanged) by increasing or decreasing the slope of the wedge shapes. Ashallower slope provides a greater mechanical advantage, whereas asteeper slope provides a lesser mechanical advantage but does notrequire a large input distance.

The mechanical advantage reduces the force acting on the horizontalfasteners 20 and hence reduces stress and stretching endured by thehorizontal fasteners 20. The non-parallel angle between the horizontalfasteners 20 and the direction of the compressive force allows the shocktest assembly 10 to withstand larger shocks and enables shocks to beabsorbed by the left and right brackets 12, 14 rather than thehorizontal fasteners 20.

The shock test assembly 10 reduces edge loading on the specimen 100,which reduces damage to the specimen 100. That is, compression isdistributed evenly from the lower cap 16 and upper cap 18 to thespecimen 100 instead of being concentrated near corners and edges of thespecimen 100. This is due to the force of the horizontal fasteners 20indirectly contributing to the compression via the wedge shapes of thelower cap 16 and upper cap 18. The shock test assembly 10 is lightweightand easy to use, thereby preventing operator error.

The shock test assembly 10 can accommodate specimens of different sizesand shapes. To that end, the left and right brackets 12, 14 can be drawntoward each other until the lower and upper caps 16, 18 contact thespecimen. For example, the left and right brackets 12, 14 may be drawncloser together for a smaller specimen than for a taller specimen. Thelower and upper caps 16, 18 can also be replaced with caps of differentsizes or shapes for testing different sized specimens.

The left and right brackets 12, 14 each form a single structure thatbuttresses the specimen 100 between the top side of the specimen 100 andthe bottom side of the specimen 100 via the vertical legs 40, 42 andcross-member 44 of the left bracket 12 and the vertical legs 64, 66 andthe cross-member 68 of the right bracket 14. This improves rigidity ofthe shock test assembly 10 with the specimen 100. In contrast,conventional shock test assemblies do not buttress a specimen via anysingle component, which may compromise test results.

The shock test assembly 10 can be used without horizontal fasteners insome embodiments. To that end, the left and right brackets 12, 14 can beforce-wedged together, whereby friction between the left and rightbrackets 12, 14 and the lower and upper caps 16, 18 (with verticalfasteners securing the shock test assembly 10 to a shock table or otherexternal structure) keeps the shock test assembly 10 together. This canbe achieved for small (i.e., shallow) wedge angles.

The shock test assembly 10 has been described with wedge shaped caps. Asingle wedge shape may be used to provide the mechanical advantage.Other mechanical advantage sources may be used, such as a cam, alinkage, a lever, a helical thread, a gear, a pneumatic system, ahydraulic system, a chain or belt drive, a pulley, or the like.

Although the invention has been described with reference to theembodiments illustrated in the attached drawing figures, it is notedthat equivalents may be employed and substitutions made herein withoutdeparting from the scope of the invention as recited in the claims.

Having thus described various embodiments of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:

The invention claimed is:
 1. An assembly for shock testing a specimenhaving a lower side and an upper side, the assembly comprising: firstand second opposing brackets each having upper angled surfaces, thefirst and second opposing brackets being configured to be positionedlaterally relative to each other; and a wedge-shaped upper cap having: alower surface configured to abut the upper side of the specimen; andfirst and second angled surfaces, the upper angled surfaces of the firstand second opposing brackets being configured to engage the first andsecond angled surfaces of the upper cap, wherein the brackets impart aforce on the cap when the brackets are drawn together so that the capimparts a longitudinal compressive force on the specimen, a direction ofthe longitudinal compressive force and a direction of the force impartedby the brackets being non-parallel relative to each other.
 2. Theassembly of claim 1, wherein the cap is a wedge-shaped lower cap havingan upper surface configured to abut the lower side of the specimen. 3.The assembly of claim 1, wherein the cap is a wedge-shaped upper caphaving a lower surface configured to abut the upper side of thespecimen, the assembly further comprising: a wedge-shaped lower caphaving an upper surface configured to abut the lower side of thespecimen.
 4. The assembly of claim 3, wherein the lower cap has firstand second angled surfaces, the upper cap has first and second angledsurfaces, the first bracket has a lower angled surface and an upperangled surface, and the second bracket has a lower angled surface and anupper angled surface, the lower angled surfaces of the first and secondbrackets being configured to engage the first and second angled surfacesof the lower cap, the upper angled surfaces of the first and secondbrackets being configured to engage the first and second angled surfacesof the upper cap.
 5. The assembly of claim 4, wherein the upper cap hasa double-wedge shape and the lower cap has an upside-down double-wedgeshape.
 6. The assembly of claim 4, the angled surfaces being inclinedbetween 1 degree and 30 degrees.
 7. The assembly of claim 4, the firstand second brackets each including a base and a riser extendingvertically from the base, the base and the riser forming a through-spacehaving lower and upper ends, the lower angled surface being at the lowerend of the through-space, the upper angled surface being at the upperend of the through-space, the through-spaces being configured to bealigned with each other for receiving at least portions of the lower capand upper cap.
 8. The assembly of claim 7, each base including aplurality of vertically-extending through-holes for fastening theassembly to an external structure via bolts.
 9. The assembly of claim 3,the lower cap having a lip encircling the upper surface and the uppercap having a lip encircling the lower surface, the lips being configuredto retain the specimen between the lower cap and the upper cap.
 10. Theassembly of claim 1, further comprising fasteners configured to draw thefirst and second opposing brackets together in a direction non-parallelwith the direction of the longitudinal compressive force.
 11. Theassembly of claim 10, wherein the fasteners are configured to laterallydraw the first and second opposing brackets together in a directionperpendicular to the direction of the longitudinal compressive force.12. An assembly for shock testing a specimen having a lower side and anupper side, the assembly comprising: first and second opposing bracketsconfigured to be positioned laterally relative to each other, eachbracket including: a horizontally-extending base; a riser extendingvertically from the base, the riser and base forming a through-spacehaving an upper end and a lower end; a lower angled surface at the lowerend of the through-space; and an upper angled surface at the upper endof the through-space; a wedge-shaped lower cap including: an uppersurface configured to abut the lower side of the specimen; and lowerangled surfaces configured to engage the lower angled surfaces of thefirst bracket and second bracket; and a wedge-shaped upper capincluding: a lower surface configured to abut the upper side of thespecimen; and upper angled surfaces configured to engage the upperangled surfaces of the first bracket and second bracket, wherein thebrackets impart a force on the lower cap and upper cap when the bracketsare drawn together so that the lower cap and upper cap impart alongitudinal compressive force on the specimen, a direction of thelongitudinal compressive force and a direction of the force imparted bythe brackets being non-parallel relative to each other.
 13. The assemblyof claim 12, the first and second opposing brackets including fastenerholes, the assembly further comprising fasteners configured to beinserted into the fastener holes to laterally draw the first and secondopposing brackets together.
 14. The assembly of claim 12, the first andsecond brackets being identically shaped, the lower cap and the uppercap being symmetrical about a vertically extending plane.
 15. Theassembly of claim 12, the angled surfaces being inclined between 1degree and 30 degrees.
 16. The assembly of claim 12, each base includinga plurality of vertically-extending through-holes for fastening theassembly to an external structure via bolts.
 17. The assembly of claim12, the lower cap having a lip encircling the upper surface and theupper cap having a lip encircling the lower surface, the lips beingconfigured to retain the specimen between the lower cap and the uppercap.
 18. An assembly for shock testing a specimen having a lower sideand an upper side, the assembly comprising: first and second opposingL-shaped brackets configured to be positioned laterally relative to eachother, each bracket including: a horizontally-extending base including aplurality of vertically-extending through-holes for fastening theassembly to an external structure; a riser extending vertically from thebase, the riser including a plurality of horizontally-extending fastenerholes, the riser and base forming a through-space having an upper endand a lower end; a lower angled surface at the lower end of thethrough-space; and an upper angled surface at the upper end of thethrough-space; a lower cap including: an upper surface configured toabut the lower side of the specimen; a lip encircling the upper surfacefor retaining the lower side of the specimen in engagement with theupper surface; and lower angled surfaces configured to engage the lowerangled surfaces of the first bracket and second bracket; an upper capincluding: a lower surface configured to abut the upper side of thespecimen; a lip encircling the lower surface for retaining the upperside of the specimen in engagement with the lower surface; and upperangled surfaces configured to engage the upper angled surfaces of thefirst bracket and second bracket, wherein the through-spaces of thebrackets are configured to receive at least portions of the lower cap,upper cap, and specimen, the angled surfaces being inclined between 1degree and 30 degrees; and a plurality of bolts configured to beinserted into the horizontally-extending fastener holes, wherein thebrackets impart forces on the lower cap and upper cap when the bracketsare drawn together so that the lower cap and upper cap impart alongitudinal compressive force on the specimen, a direction of thelongitudinal compressive force and a direction of the force imparted bythe brackets being non-parallel relative to each other.
 19. An assemblyfor shock testing a specimen having a lower side and an upper side, theassembly comprising: first and second opposing brackets configured to bepositioned laterally relative to each other, the first and secondopposing brackets each having a lower angled surface and an upper angledsurface; a wedge-shaped upper cap having a lower surface configured toabut the upper side of the specimen and first and second angledsurfaces; and a wedge-shaped lower cap having an upper surfaceconfigured to abut the lower side of the specimen and first and secondangled surfaces, the lower angled surfaces of the first and secondbrackets being configured to engage the first and second angled surfacesof the lower cap, and the upper angled surfaces of the first and secondbrackets being configured to engage the first and second angled surfacesof the upper cap, wherein the first and second brackets are configuredto impart a force on the upper cap and the lower cap when the first andsecond brackets are drawn together so that the upper cap and the lowercap impart a longitudinal compressive force on the specimen, a directionof the longitudinal compressive force and a direction of the forceimparted by the brackets being non-parallel relative to each other. 20.The assembly of claim 19, wherein the upper cap has a double-wedge shapeand the lower cap has an upside-down double-wedge shape.
 21. Theassembly of claim 19, wherein the lower angled surfaces and upper angledof the first and second opposing brackets and the first and secondangled surfaces of the upper cap and lower cap are inclined between 1degree and 30 degrees.
 22. The assembly of claim 19, wherein the firstand second brackets each include a base and a riser extending verticallyfrom the base, the base and the riser forming a through-space havinglower and upper ends, the lower angled surface being at the lower end ofthe through-space, the through-spaces of the first and second bracketsbeing configured to be aligned with each other for receiving at leastportions of the lower cap and upper cap.
 23. The assembly of claim 19,each base including a plurality of vertically-extending through-holesfor fastening the assembly to an external structure via bolts.
 24. Theassembly of claim 19, the lower cap having a lip encircling the uppersurface of the lower cap, the upper cap having a lip encircling thelower surface of the upper cap, the lips being configured to retain thespecimen between the lower cap and the upper cap.